Process for treating endless tow of fiber with bath liquid



Jun 13, 1967 SHOJI KUROSAKI PROCESS FOR TREATING ENDLESS TOW OF FIBER WITH BATH LIQUID Filed July 26, 1965 INVENTOR Shoji Kurosaka ATTORNEYS 3,324,486 PROCESS FOR TREATING ENDLESS TOW F FIBER WITH BATH LIQUID Shoji Kurosaki, Okayama, Japan, assignor to Kurashiki Rayon Co., Ltd., Kurashiki, Japan Filed July 26, 1965, Ser. No. 474,804 Claims priority, application Japan, July 31, 1964, Sit/43,764 1 Claim. (Cl. 8-151) This invention relates to a process for continuously treating an endless tow of fiber in the state separated into individual filament units, and an apparatus therefor.

In liquid treating fibers, the methods heretorfore used and known consist of feeding a large number of filaments in parallel into a tow form, into a U-shaped or J-shaped bath, filling the tow in a coiled state or folded state into the bath liquid, and thus to treat the tow successively. By the ordinary methods, the tow is treated as such, not separated into filament units, in order to prevent tangling of the filaments as the tow is taken out of the bath. This involves many difficulties. For example, because the tow which is not separated into individual filament units is filled in the bath, the uniform treatment of tow with the bath liquid cannot be readily attained and therefore takes a long time before it is treated to any satisfactory extent.

The principal object of the invention is to eliminate all such difficulties and disadvantages of the conventional methods and to provide a process for uniformly and continuously treating a tow in the state of individually separated filament units with reduced filling density of the fiber in the bath liquid.

Another object of the invention is to provide a process for uniformly treating a tow in the form of individually separated filament units.

Further object of the invention is to provide a process for treating a tow within a relatively short period of time by treating the tow in the form of individually separated filament units.

Still further object of the invention is to provide an apparatus suitable for embodying the process of the invention.

In carrying out the invention, the tow to be charged in the treating bath is dropped together with a large amount of a treating solution or bath liquid, onto the liquid surface in the bath, so as to give an impact to the endless tow of fiber thereby to separate the tow into individual filament units, and the tow is fed into the bath continuously in this way. The filament separation must be effected sufliciently to reduce the filling density of the fiber in the bath liquid and to permit uniform treatment of the fiber with the chemical solution. If the tow alone is supplied to the bath, it will scarcely be separated into filament units, even though it is supplied at a fairly high velocity. It is therefore important to impregnate the tow beforehand with the bath liquid and to feed the tow together with the liquid thereby to facilitate separation of the tow in the bath. In order to impregnate the tow sufficiently with the solution, it may be dipped in a bath for preliminary treatment which is filled with the same bath liquid and then supplied together with the liquid into the main bath, or the tow may be supplied from above the bath downwardly and then impregnated midway with jets of the liquid. Numerous other procedures are applicable for the purpose. The fibers to which the present invention is applicable include all the synthetic fibers of endless tow available in the form of tows. The effectiveness of the process of the invention is particularly demonstrated when the tow to be treated is voluminous, for example a tow with a total denier 3,324,486 Patented June 13, 196'] of more than 10,000. Of course, the invention is applicable to tows of less total deniers.

The types of fibers which are advantageously treated in accordance with the invention include synthetic fibers such as polyacrylonitrile, polyvinyl alcohol, polyurethane, polyolefin, polyamide, and polyester fibers, semi synthetic fibers such as acetate, and regenerated fibers such as viscose rayon and cupro-arnmonium rayon. Although it is desirable that the treating solution has a specific gravity greater than that of the fiber to be treated, any liquids having a specific gravity equivalent to more than percent of that of the fiber may be used. If a treating solution is used which has an extremely low specific gravity as compared with that of the fiber, the Sinking velocity of the endless tow of fiber in the bath will be too high to permit thorough separation of the tow into filaments, and thus the tow will be deposited at the bottom of the bath, causing tangling of the filaments and other troubles in subsequent paralleling of the filaments, and making it impossible to effect uniform treatment and hence to attain a satisfactory effect of treatment. For giving an impact to the tow at the liquid surface in the hath, no special arrangements are necessary. In dropping a tow together with a large amount of a treating solution, if the tow is fed at a velocity substantially same as the dropping velocity of the solution, the tow is given, as a result, an impact on the liquid surface of the bath, and the filaments constituting the tow are separated into individual filament units, over a broad width, and sink slowly as if folded down on the bottom of the bath, while being subjected to a uniform treatment.

The endless tow of fiber charged in a bath in accordance with the invention is separated completely into filament units in the bath liquid, and has an increased resistance in the liquid. Therefore, the sinking velocity of the endless tow is very low .as compared with the feeding velocity. The endless tow of fiber treated in the bath While separated into individual filament units must be gathered again to a tow form. According to the invention, the filaments filled in the bath are pulled out from the bottom of the fiber layer and passed through the bath at a velocity above a certain value, so that the fiber separated into individual filament units can be arranged in parallel by the frictional resistance to the liquid and can be taken out of the bath again in the form of a tow.

For a better understanding of the invention reference is taken to the accompanying drawing, of which a single figure is a diagrammatic sectional elevation of an apparatus for carrying out the process of the invention.

Referring to drawing, the inlet side of a U-shaped cylindrical bath 14 includes a pair of feed rolls 7 above the straight pipe portion 1, and a treating solution is sprayed through an inlet port 6 for the tow 13- as the latter is charged into the bath 14 by means of said feed rolls 7, so that the tow is dropped together with the treating solution onto the liquid surface of the bath. The inlet port may have one or more nozzles facing the tow in order that the treating solution can be supplied uniformly to the tow. Most preferably the nozzles are arranged at several points to encircle the tow.

The outlet side of the U-shaped cylindrical bath 14 comprises a squeezing guide 5 and a squeezing delivery roll 4 above the straight pipe portion 3 on the outlet side. The bottom pipe portion 2 as well as the straight pipe portion 3 on the outlet side are not packed with the tow but are used to parallel the filaments in order to reshape them to a two with the aid of the liquid resistance caused by the relative velocities of the tow being taken out and also of the bath liquid.

The chemical solution in the bath can be maintained at a required concentration by providing an overflow port 9 for the bath liquid on the upper portion of said straight pipe 3 so as to send back part of the liquid supplied by the feed pipe 8 and nozzle 6 on the inlet side. The numeral 15 indicates a drainage pipe. In the apparatus shown, the length of the straight pipe portions 1 and 3 is preferably more than 2,000 mm. respectively, though it depends on the amount of tow to be filled in, the required period of treatment, desired denier and type of the tow fiber, and other factors. The drawing speed of the endless tow of fiber in this case is preferably from 15 to 60 meters per minute. The height (or head) of the nozzle 6 for supplying the treating solution together with the tow, from the liquid level of the bath is preferably from 800 to 1,200 mm, though it depends upon the total denier of the endless tow of fiber, the type of fiber or of the bath liquid, and other factors.

As shown in the accompanying drawing, the apparatus according to the invention is provided with a tow-winding detector 10, a tow-slipping detector 12, and a staying time detector 11 to permit detection of winding and slipping of the tow on the rolls and determination of the staying time of the tow at regular intervals of time, to a great practical advantage in operating the apparatus without troubles and performing constant quality control. Also, rolls or guides may be provided in the apparatus, to be submerged in the bath liquid, preferably on the outlet side.

As described hereinbefore, the process of the invention is very suitable for liquid treatments of endless tows of fibers, including liquid treating, dyeing, acetalizing, and washing with water, and it permits the treatments to be accomplished at increased rates and with very limited unevenness of the treatment effects.

The process of the invention is illustrated by the following examples.

Example 1 A 500,000-denier tow of a polyvinyl alcohol synthetic fiber, spun, hot drafted and heat treated in the usual manner, was fed into a U-shaped bath partly filled with an acetalizing solution containing formalin in a concentration of 30 g./1it., sulfuric acid in a concentration of 250 g./lit., and a small amount of Glaubers salt, by dropping the tow continuously from above the inlet of one of the straight pipe portions of the bath, together with a treating solution or bath liquid of the same composition as thatin the bath and which is sprayed over the tow from a nozzle at a height of 900 mm. from the liquid surface of the bath, whereby the tow was treated in the state of individually separated filament units in the bath. The specific gravity of the treating solution was 1.30. The filaments in the separated state were led from the bottom of the inlet side of the U-shaped cylindrical apparatus toward the pipe portion on the outlet side, where the filaments were arranged in parallel and taken out continuously from the top end of said pipe portion. The drawing velocity of the tow was 40 meters per minute, and the staying time of the tow was 30 minutes.

Then, the tow was refined, washed with water, and finished by drying in the usual manner. The tow thus obtained was uniformly acetalized.

4 Example 2 A 10,000-denier tow of a polyurethane synthetic fiber produced by an ordinary method was fed into a U-shaped bath partly filled with a dye solution containing a metal complex dye and dyeing assistant, by dropping the tow from above the inlet of one of the straight pipe portions of said treatment apparatus, together with a treating solution of the same composition as the bath liquid which was sprayed from a nozzle at a height of 1,200 mm. from the liquid level of the bath, and the tow was treated in the form of individually separated filament units. The specific gravity of the bath liquid was 1.01. The filaments in the separated state were led from the bottom of the inlet side of the U-shaped vessel toward the pipe portion on the outlet side, where the filaments were arranged in parallel and drawnout of the top end of said pipe portion. The take-off speed of the tow in this case was 30 meters per minute, and the staying time of the tow was 40 minutes. Then, the tow was refined, washed with water, and dried for finishing. The tow thus obtained was uniformly dyed.

Example 3 A 10,000-denier tow of a polypropylene fiber was fed into a U-shaped vessel partly filled with a dyeing solution containing a dispersion dye and a dyeing assistant, and was treated under the same conditions as described in Example 2. The tow was uniformly dyed in a continuous and simple operation. The specific gravity of the treating solution was 1.02, and the staying time was 40 minutes.

Example 4 A 10,000-denier tow of a polyurethane synthetic fiber was refined (with a non-ion activator) and bleached (with a chlorine bleaching agent) in a U-shaped tubular vessel under the same conditions as in Example 2, in accordance with the invention. The refining and bleaching solutions both had the same specific gravity of 1.02, and the periods of time required for the treatments were both 30 minutes. The product was very uniformly refined and bleached.

What I claim is:

A process for the continuous treatment of endless tows of fibers which comprises dropping a tow together with a treating solution on a bath separating the tow into individual filament units by the impact on the liquid surface of the bath, effecting the reaction of the filament units in a low filling density, and then paralleling the filaments to a tow form and taking out the tow from the bath.

References Cited UNITED STATES PATENTS 1,074,567 9/1913 Gantt 68-178 1,665,624 4/1928 Conrad 68-62 3,007,225 11/1961 Becker et al 8-152 X 3,066,006 11/1962 Sonnino 8151.2 3,152,464 10/1964 Faraguna 68-179 X IRVING BUNEVICH, Primary Examiner. 

